In humid, tropical climates this will not work.
MotherEarth had an article on building a solar-powered freezer that uses ammonia gas. Use that to make ice, and then use the ice in an ice-box like storage device.
http://www.scribd.com/doc/6599651/How-to-Build-a-Solar-Icema...
Yeah, clay is easier to find than the other materials, but the ammonia freezer does work without any moving parts.
My google-fu is failing me this evening, and this is about the best I can come up with http://www.earthgarden.com.au/kerosene.html
This was hot on the heels of the 1970s energy crisis and the solar technology boom; I wonder in what ways the drive to innovate appropriate technology has changed since then.
By only freezing water to make ice and to keep an icebox cool (the icebox and where you freeze the water are two seperate physical locations), you reduce the risk of any ammonia related injury or contamination.
You would just have a bunch of 1 gallon jugs of water you freeze and swap out between the icebox and the freezer).
Like the olds days!